I had the same problem with Magtech 260gr when I got my SRH. When I contacted Ruger, the first question they asked was were you using Hornady ammo. So it seems there are some "trouble" ammos out there. All Winchester loads, and most handloads I have tried have funtioned flawlessly. The only problem handloads I had were using Hornady 250gr which I found out were for .45colt velocities only. Switched to Hornady 240 or Speer 260mag and no more problems. All my handloads have been in Starline brass, high quality stuff, I doubt that is the problem. If all else fails, as has been suggested get on the horn with Corbon.